1. Field of the Invention
The present invention relates to a carbon material and an electricity storage device.
2. Description of the Related Art
Carbon materials can be used in electrodes of electricity storage devices such as electric double-layer capacitors, hybrid capacitors and lithium-ion secondary batteries.
For example, JP-A 9-293507 describes use of fine powder produced by carbonizing a phenol resin as a material for a negative electrode of a lithium-ion secondary battery. This fine powder features a cumulative pore volume V1 of 0.05 to 0.35 mL/g for a pore diameter interval of 0.28 to 0.50 nm, a ratio V2/V1 of 0.30 or less, which is a ratio of a cumulative pore volume V2 for a pore diameter interval of 0.50 to 1.0 nm with respect to the cumulative pore volume V1, and a ratio V3/V1 of 0.25 or less, which is a ratio of a cumulative pore volume V3 for a pore diameter interval of 1.0 nm or more with respect to the cumulative pore volume V1. The fine powder also features a specific surface area of 1 to 500 m2/g, an average particle diameter of 0.1 to 50 μm, and an atomic ratio of hydrogen atoms with respect to carbon atoms of 0.02 to 0.35.
JP-A 2006-324183 describes use of carbon particles having particle diameters of 100 nm to 10 μm as a material for a negative electrode of a lithium-ion secondary battery. This second patent document also describes use of an activated carbon having particle diameters of 100 nm to 10 μm, a pore diameter of 2 to 5 nm, and a pore volume of 0.1 to 2.0 mL/g for a pore diameter interval of 2 to 5 nm as an active material of an electric double-layer capacitor.